The field of the invention relates generally to nano-fabrication of structures. More particularly, the present invention is directed to a method for filling a recess of a patterned substrate for use in imprint lithography.
Nano-fabrication involves the fabrication of very small structures, e.g., having features on the order of nanometers or smaller. One area in which nano-fabrication has had a sizeable impact is in the processing of integrated circuits. As the semiconductor processing industry continues to strive for large production yields while increasing the circuits per unit area formed on a substrate, nano-fabrication becomes increasingly important. Nano-fabrication provides greater process control while allowing increased reduction of the minimum feature dimension of the structures formed. Other areas of development in which nano-fabrication have been employed include biotechnology, optical technology, mechanical systems and the like.
An exemplary nano-fabrication technique is commonly referred to as imprint lithography and is described in detail in numerous publications, such as United States published patent application 2004/0065976 filed as U.S. patent application Ser. No. 10/264,960, entitled “Method and a Mold to Arrange Features on a Substrate to Replicate Features having Minimal Dimensional Variability”; United States published patent application 2004/0065252 filed as U.S. patent application Ser. No. 10/264,926, entitled “Method of Forming a Layer on a Substrate to Facilitate Fabrication of Metrology Standards”; and United States published patent application 2004/0046271 filed as U.S. patent application Ser. No. 10/235,314, entitled “Method and a Mold to Arrange Features on a Substrate to Replicate Features having Minimal Dimensions Variability”; all of which are assigned to the assignee of the present invention. The fundamental imprint lithography technique as shown in each of the aforementioned published patent applications includes formation of a relief pattern in a polymerizable layer and transferring a pattern corresponding to the relief pattern into an underlying substrate. To that end, a template, having a template active area, is employed spaced-apart from the substrate with a formable liquid present between the template and the substrate. The liquid is solidified to form a solidified layer that has a pattern recorded therein that is conforming to a shape of the surface of the template active area. The substrate and the solidified layer are then subjected to processes to transfer, into the substrate, a relief image that corresponds to the pattern in the solidified layer.
One manner in which to locate the polymerizable liquid between the template and the substrate is by depositing the liquid on the substrate. Thereafter, the polymerizable liquid is concurrently contacted by both the template and the substrate to spread the polymerizable liquid over the surface of the substrate and fill the features of the template. It is desirable to minimize the time required to fill the features of the template, referred to as fill time. Thus, there is a need to provide improved techniques to fill the features of a template.